Research On Low-Temperature Deposition Printing Process For Alginate/gelatin

3D printing technology has become a hot spot in rapid prototyping technology based on the processing capability of complex structure and bio-printing technology in tissue engineering.With the development of bio-printing technology,the development and application of printed materials are becoming more and more diverse.As a biological material alginate/gelatin is widely used,Its stable and easy-forming properties play an important role in 3d extrusion printing.As the carrier of cell culture and the pore of providing nutrition channel for cells,the structure of bio-gel scaffold has been increased to micron level.However,the method of traditional gel preparation has been difficult to meet the requirements of micropore in precision,and the Low-Temperature Deposition Manufacturing(LDM)has made it possible.With the development of cell printing technology,it is urgent to find a method to improve the accuracy of 3D printing.Gradually with the improvement of technical bottleneck,The accuracy requirement for conducting sodium alginate/gelatin three dimensional extrusion printing process of development in the field of research for the finer structure has the very vital significance.Based on the analysis of the characteristics of the material,this paper studies the 3d extrusion process comprehensively and systematically,The characteristics of non-newtonian fluid in sodium alginate/gelatin were analyzed.The influence of extrusion swelling and stretching in the process of printing was analyzed for the configuration of different materials,And then the printing research of the basic structure of point and line is extended to the process of plane and stereo structure printing.(1)The optimum ratio of sodium alginate and gelatin composite materials:The mechanical properties and quality were determined by the crosslinking reaction of sodium alginate/gelatin and calcium chloride and from the analysis of viscosity,finally,the appropriate proportion of materials was determined.The concentration range of alginate is 2%~4%.The concentration range is 6%~8%.Calcium chloride can be selected at a concentration of 3%~5%.(2)The extrusive expansion and optimum process of sodium alginate/gelatin: From the analysis of the original material characteristics,it reveals the influence of the gel line on the expansion of extruded outlet and the stretching of the nozzle movement.To give a reasonable calculation method for extrusion swelling and stretching,In the end,the optimum technological parameters affecting the swelling and the influence precision were found through experimental verification and orthogonal experimental analysis.Material viscosity 1.26 Pa.S,extrusion pressure 80 KPa,nozzle velocity 8mm/s.(3)Process of LDM printing structure control of sodium alginate/gelatin: Determining the amount of suckback during printing from the print point,the influence of linear deformation and corner on the printing structure is analyzed.finally,the technological parameters and the process structure of the three-dimensional structure are summarized.It provides theoretical basis and data reference for fine hole printing and later cell printing.